Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method for performing cleaning treatment on a substrate.
Description of the Background Art
Substrate processing apparatuses which perform a drying process after performing surface treatments including liquid chemical treatment using a liquid chemical, rinsing treatment using a rinsing liquid such as deionized water, and the like on substrates have hitherto been used in the steps of manufacturing substrates. Examples of such substrate processing apparatuses which have been used include a single-wafer type apparatus which processes substrates one by one, and a batch type apparatus which processes substrates in one batch.
In general, the single-wafer type substrate processing apparatus performs the liquid chemical treatment which supplies a liquid chemical to a surface of a rotating substrate and the rinsing treatment which supplies deionized water to the surface of the rotating substrate, and thereafter rotates the substrate at a high speed to perform a spin-drying process. At this time, the greater part of such a processing liquid flying off to adhere to the inner wall of a cup surrounding a spin chuck flows downwardly along the inner wall of the cup and is then drained. However, part of the processing liquid on the inner wall of the cup remains adhering thereto and is not collected in some cases. The processing liquid adhering to the inner wall of the cup becomes particles, when dried, to become a cause of contamination of the substrate. To prevent this, cup cleaning treatment for cleaning the cup is in general performed each time a specific number (typically, a specific lot) of substrates are processed. Such a single-wafer type substrate processing apparatus is disclosed in U.S. Patent Application Publication No. 2012/273011, for example.
The substrate processing apparatus disclosed in U.S. Patent Application Publication No. 2012/273011 includes: a spin chuck for rotating a substrate while holding the substrate in a substantially horizontal attitude; a nozzle for supplying a processing liquid onto the upper surface of the substrate held by the spin chuck; and a cup surrounding the spin chuck and for receiving the processing liquid flying off from the substrate.
In this substrate processing apparatus, the rinsing liquid (typically, deionized water) is supplied to a spin base portion (circular plate-like portion) of the spin chuck rotating without holding the substrate. The supplied rinsing liquid is flown off from the spin base to the cup and its surroundings by centrifugal force caused by the rotation. Thus, the places to which the rinsing liquid is flown are cleaned.
Unfortunately, the technique of supplying the rinsing liquid to the rotating spin base to fly off the rinsing liquid as disclosed in U.S. Patent Application Publication No. 2012/273011 causes the rinsing liquid to collide with chuck mechanisms (typically, of a protruding shape) included in the spin chuck and for grasping the substrate, thereby making it difficult in some cases to fly off the rinsing liquid appropriately to the places to be cleaned to which the liquid chemical adheres.
There is another technique in which a substrate processing apparatus includes a tool designed specifically for the cup cleaning treatment, and the rinsing liquid is supplied to the cleaning tool grasped and rotated by the spin chuck. This technique avoids the aforementioned problem of the collision of the rinsing liquid with the chuck mechanisms, but presents another problem such that the cleaning tool must be attached and detached for every cup cleaning treatment to result in the decrease in throughput. The provision of the component designed specifically for the cup cleaning treatment in addition to the components required for the substrate processing gives rise to another problem such that the substrate processing apparatus is increased in size.
In this type of substrate processing apparatus, it is common practice to perform the aforementioned cup cleaning treatment during a time interval between the end of the substrate processing of a lot (a specific number of substrates in a group to be subjected to the same processing) and the start of the substrate processing of its subsequent lot. For this reason, if there arises a need to perform the aforementioned cup cleaning treatment in the middle of the lot processing, it has been difficult to start the cup cleaning treatment before the completion of the lot processing being performed.